3D-IC packaging is widely seen as an important avenue for maintaining traditional increases in semiconductor performance. Through-silicon vias (TSVs), the foundation of the 3D-IC revolution, are a key enabler for these increases. But only small, high-density vias can provide reduced thermo-mechanical stress, improved signal integrity and efficient use of on-chip real estate.
TSVs of this type, with aspect ratios of 10:1 and higher, cannot be manufactured with acceptable costs and yields using traditional dry processes for liner, barrier and seed deposition. Basic shortcomings of i-PVD copper seed and CVD/ALD barrier coverage in deep TSVs, coupled with high capital costs, are holding back the industry-wide adoption of 3D-IC solutions.
Alchimer’s fluid-based processes can easily reach the sides and bottoms of TSVs, and quickly deposit extremely uniform film stacks (isolation, barrier and fill) that are atomically fused to the TSV’s surface. This eliminates voids, opens, and shorts, enabling higher yields while also providing substantial cost savings in both capital investment and ongoing operations.
Our processes’ exceptional capability also means that circuit designers can utilize narrower TSVs, which take up less space on the silicon die – another means of cutting cost or improving performance.
Alchimer offers a suite of products that bring Electrografting’s breakthrough results to the manufacturing line. All our products offer a combination of conformality, step coverage and purity that cannot be matched by dry processes. Customers may choose a single film or any combination of films and fills, based on their application needs.
- eG3D Isolation – eG3D Isolation provides an isolation film for the dielectric liner. We use a polymer with an elasticity modulus and stress value that provide a thermo-mechanical buffer between Si and Cu. The Electrografting technology allows the polymer chains to form a very dense and compact film with superior electrical properties.
- cG3D Barrier – cG3D Barrier utilizes a NiB compound to create Cu diffusion barrier properties equivalent to dry TiN or TaN barriers, while maintaining resistivity levels that enable fill without the need for a Cu seed layer.
- eG3D Seed – eG3D Seed deposits extremely high-quality Cu seed layers. It provides all the advantages of the Electrografting technology in applications where a seed layer is desirable.
- eG3D Fill – eG3D Fill provides the final fill step for deep-and-narrow through-silicon vias. It provides larger and more uniform grain sizes than industry-standard processes, and because it does not require additives typical of standard ECD fills, the purity of the bath is significantly higher.